Stabilization of regenerated cellulose



Nov. 14, 1950 E. c. PFEFFIIER, JR., EFAL 2,530,175

STABILIZATION 0F REGENERATED CELLULOSE Filed Sept. 27, 1946 2 Sheets-Sheet l 2.0 PERCENT BY VOLUME ALUMINUM ACETATE (20% SOLIDS) 3 g a OHVA 83d SHHONI -39V |NIHHS 'IVI'ICIISEIH INVENTORS EDWARD C. PFEFFER JR.

$90K. EPELBERG 6114 1% ATTY;

FIGJ

Q 14,1950 E. c. PFEFFER, JR, ETAL 2,530,175

STABILIZATION OF REGENERATED CELLULOSE Filed Sept. 27, 1946 2 Sheets-Sheet 2 RESIDUAL SHRINKAGE INCHES PER YARD N F F 275 F F CURING TEMPERATURE INVENTORS EDWARD c. PFEFFER JR. H62 JACK EPELBERG A IM Patented Nov. 14, 1950 STABILIZATION OF REGENERATED CELLULOSE Edward C. Pfeffer, Jr., and Jack Epelbcrg, Troy, N. Y., assignors to Oluett, Peabody & Co., Inc., Troy, N. Y., a corporation of New York Application September 27, 1946, Serial No. 699,626

9 Claims. (Cl. 8-1164) This invention relates to textiles, and more particularly to the novel method of treating textiles formed predominantly of regenerated cellulose, so as to render them substantially stable with respeotto laundry shrinkage and also resistant to crushing and creasing. This application is a continuation in part of our co-pendingapplication S. N. 576,755 filed February 8, 1945, now abandoned, and entitled Stabilized Textiles. The present invention is in the nature of an improvement overthat described and claimed in our application S. N. 644,188 filed J anuary 29, 1946 for Textile Materials and Method of Preparing the Same and an earlier application S. N. 495,620 filed July 21, 1943 of which the application S. N. 644,188 was a continuation in part, both now abandoned. Y

The terms textile material and textile are intended to include filaments and fibers, staple or yarns, whether in the finished stage or at some intermediate stage in the production thereof, and also to include fabrics whether knitted, woven or felted, as well as garments or other articles made from such fabrics.

The aforesaid applications upon which the present invention is an improvement, disclose the employment of a dialdehyde, more particularly glyoxal, in substitution for the formaldehyde-previously employed for the purpose, and points out that highly satisfactory results, as respects shrinkage stabilization, accompanied by increased crush resistance and resistance to creasing and wrinkling, may be obtained by the use of a dialdehyde so reacted; in the presence-of an acid catalyst, with the regenerated cellulose of the textile materiaLas to convert or at least partially to convert each fiber into a reaction product which is more resistant to moisture and the effects 'of laundering than the original fiber. It was further pointed out that while a dialdehyde may be expected to act in a generally similar manner to formaldehyde in the formation of a long-chain polymer, the presence of the two aldehyde groups in primary linkage may be expected to cause the dialdehyde to form a cross linked long-chain reaction product with the cellulose, thus producing a more permanent effect than formaldehyde, and resulting in a product characterized, it appears, by less relative slippage of the molecular chains, so that the material is more resistant to crushing and creasing than the untreated material, or one which has been treated with formaldehyde or compounds thereof. It was further noted that the dialdehyde known as glyoxal is highly useful for the sta bilization of textile materials formed predominantly of regenerated cellulose, including filaments, fibers, staple or yarns, and fabrics whether knitted, woven, braided or felted, as well as garments or other articles made from such fabrics. Glyoxal has but little odor in solution of a strength suitable for such treatment (such odor as it has being pleasant), it does not emit disagreeable or toxic fumes during curing, it does not'tender the textile materialnor make it brittle, it does not discolor nor brown the material to anyharmful degree, and it may readily be applied without necessitating special equipment, and is effective in smaller quantities than the reagents previously employed for the purpose.

Glyoxal is available in substantial quantities only in a commercial form as animpure aqueous solution. This commercialform is a pale straw colored solution containing approximately 30% by weight of glyoxal in water, and it is highly acid with a pH of between about 1.00 and 1.30. It has a specific gravity at 20/20 C. of 1.24 to 1.28.

When a 30% byweight glyoxal solution having a pH of about 1.12 is diluted with water so as to contain about 120 cc. glyoxal per litre, the pH of the solution is then approximately 2.05. The water used for such dilution was approximately neutral with a .pH of 7.2.

The principal'object of the present invention is to provide a novel method whereby the treatment with glyoxal is greatly accelerated and the time and temperature, required for curing the treated materials is reduced, and improved shrinkage control is obtained. Other and fur.- ther objects and advantages, of the invention will be pointed gout in the following more detailed description and by reference to the accompanying draWings herein Fig. 11s, a graph illustrating the effects upon shrinkage control of variations in the concentration of the promoter employer; and

Fig. 2 is a graph illustrating the effect upon shrinkage control of variations in the curing temperature. 7

The present invention is based upon the discovery that the reaction between glyoxal andregenerated cellulose in the presence of an acid catalyst, is greatly accelerated by the addition of small amounts of those aluminum salts which are either soluble in water or are readily dispersible in water. This results in improved shrinkage control and permits lower curing temperatures and/or decreased curing time. The milder curing conditions result in the elimination of possible damagetothe fabric which might come from high baking temperatures and long baking time, the stabilizing process being made commercially more feasible, because of these less severe conditions required for curing.

This use of aluminum salts to accelerate the treatment with glyoxal appears to be wholly novel and the results attained are such as could not be predicated upon the known properties of aluminum salts, since the result of the addition of the aluminum salts to the treating solution is synergic, that is to say, the effect is greater than additive. Aluminum salts alone, unless highly acid by disassociation, do not catalyze the reaction between glyoxal and'cellulose. The presence of acid is required for effective reaction between glyoxal and cellulose, and the aluminum salt added to this solution constitutes a promoter for the reaction. A promoter has been defined as a substance which increases the catalytic activity to an extent exceeding the additive effect.

Only a very low concentration of reagents is required in obtaining the desired results, and in fact harmful effects may be experienced with larger concentrations of reagents. As illustrative; without limitation of the scope of the invention, the following examples of reagent strengths and conditions of treatment are cited:

1. Amount of glyoxal: 30 to 200 cubic cms. of 30 by weight of commercial glyoxal solutionper liter of treatingbath, or 1.12% to 7.5% glyoxal by weight in the aqueous treating bath.

2. Type of catalyst: Acid-reacting, such as organic acids, or salts of inorganic acids or organic acids which produce an-acid effect.

3. Amount of acid catalyst from 1 to 20 grams per liter, approximately 0.1% to 2% by weight of the treating bath.

4. Amount of aluminum salt from 0.2 grams per liter (solid basis) 5. Baking or curing temperature: Above 212 F.

6. Baking time: Inversely related tothe baking temperature and continued-until stabilization is" substantially completed,

'7. The pH of the treating bath is between approximately 1;() and2.'5;

As pointed out in said aforesaid copending application, S. N. 644,188,.it-is. not ordinarily advisable'to usefree minerakacid's. as catalysts in the treatment of textiles, and we prefer to employ as. the catalyst such acidic reagents as oxalic acid, ammonium chlorideammonium sulfate or ammonium nitrate Oxalic acid has proven to be very satisfactory.

The graph of Fig. 2 illustrates the effects of the addition of aluminum salts to-the glyoxal treating solution containing acid catalyst. The data for this graph was obtained by treating an all spun viscoserayonchallis type fabric with the treating solutions-shown on the graph. The 100% spun viscose rayon fabric was obtained in the greige, was desized and boiled off to remove size, and was then dried on a tenter frame. The white, pure finish fabric had a residual shrinkage in one CCCT191A cotton wash of 5.5 inches per yard. In each of the series of tests upon which the respective graph is based, the pure finish fabric was immersed in the selected impregnating solution in a padder box for twelve seconds and was then run between rubber squeeze rolls to remove excess treating solution. The liquid pick-up in each case was 130% based on the dry weight of the fabric. The'impregnated fabric was then dried on a pin-tenter to the original dimensions beforeimpregnating, using circulating hot air at 250 F. and removing from the drying oven when first free from moisture. The dried fabric was then baked on the pinframe for each test at the temperature indicated on the graph for eight minutes. In each test the cured fabric was then removed from the pin-frame after curing and subjected to one CCCT191-A cotton wash test for shrinkage. The residual shinkage (from the original pure finish dimensions) was then determined as a measure of the shrinkage control of each treating solution at the different curing temperatures. In commercial practice a process loss, or shrinkage,

' can be taken by permitting the fabric to relax in a slack drying operation, but in the above experimental technique no process shrinkage is permitted prior to the test wash. Thus comparative data on shrinkage control can be accurately obtained.

In the tests made to obtain data for the graph of Fig. 2 the base treating solution, the effects of which. on fabric are illustrated by curve A, contained 4.5% glyoxal byweight and 0.6% by weight oxalic acid, the balance being water. The three other treating solutions whose effects are indicated by curves-1B, C and D, respectively, had additions, respectively, .of 3% by volume aluminum acetate solution (20% solids), 1% by weight potassium aluminumsulfate, and 3% by weight Aquarol as received. Aquarol is a proprietary water-repellent compound of non-permanent type containing'6% aluminum acetate in addition to a stable'emulsion of. hydrocarbon waxes. The 'dataand curves derived therefrom show that the addition ofxthe aluminum compounds greatly improved shrinkage control and permit a decrease in baking temperature-without any appreciable decrease in shrinkage control. Note that even-at atemperature of 290 F. which approaches the danger point as respects fabric damage, the shrinkage reduction produced by the base treating solution was not as great as that produced by the other solution at a temperature of 275 F. or less. The lower temperature bake which can be satisfactorily used with the aluminum'compound added isa practical advantage in commercial practice" and the improved shrinkage control-makes the commercial use of the process more-feasible and reduces yardage loss in processing.

The fact that the aluminum salt alone is not a catalyst for the lyoxal process is shown by the following shrinkage data which was developed in the same manner as the data used in the graph of Fig. 2;

Fabric residual shrinkage Treating Formula Inches The curingtemperature and time was 280 F. for eight minutes.

It can be seen from the above table that the treatment with glyoxal having aluminum acetate added; but without acid catalyst present, produces no effective shrinkage control but that the treatment with glyoxal with both acid catalyst and aluminum acetate added produces a result superior to that obtained with acid catalyst alone.

We find that the aluminumsalts that are suitable for this purpose are all of the aluminum salts which are either soluble in water or readily dispersible in water. A few examples of such suitable aluminum salts are aluminum formate, aluminum acetate, aluminum salts of fatty acids or soaps such as aluminum stearate, and with each of these aluminum salts we find it necessary to employ an acid catalyst. Salts of strong mineral acids, such as aluminum chloride and sulfate, are effective without added acid catalyst because such salts are highly acid by dissociation in solution, but their use is likely to result in an undesirable degree of damage to fabric tensile strength and abrasion resistance.

- Mixed salts such as potassium-aluminum sulfate are effective, with the addition of small amounts of an acidic catalyst. Where an aluminum salt that is used as the promoter, is one that does not hydrolyze to give a strongly acid solution with a pH under 2, it is necessary to use an added acid catalyst.

. The behavior of aluminum acetate as a promoter is very interesting since in small amounts it aids shrinkage control whereas in larger amounts it acts as a buffer to the acid catalyst and can even harm the degree of shrinkage control. The graph of Fig. 1 illustrates this effect. The data was obtained by the same methods and procedure as that for the graph of Fig. 2. In this case, for each test a different quantity of aluminum acetate solution (20% solids) was added to the base treating solution of 4.5% glyoxal and 0.6% oxalic acid. The curing schedule r ,o (Arkansas (30.), Textarid (Sonneborn Co.),

Aridex (E. I. du Pont de Nemours & 00.), and Drax (Johnson 00.). Aquarol" is a one bath, water-repellent finish for hosiery and piece goods, and contains a stable emulsion of hydrocarbon waxes and aluminum salts. Textarid is a stable wax emulsion used as a one bath water-repellent for rayon, silk and cotton. Aridex is a water-repellent solvent paste containing wax and an aluminum salt compound. These products are identified under these trade names in the 1945 year book, page 471, of the American Association of Textile Chemists and Colorists.

The following specific examples are given as illustrative of the application of the present novel process as a practical matter to materials of different types:

EXAMPLE #1 A plain weave; 100% spun viscose rayon challis fabric in the greige was desized, boiled off and dried on a tenter frame. The white, pure finished fabric had a count of 66 x 41 and a weight of four ounces per yard. This fabric was then passed through an aqueous impregnating solution containing per liter, 120 cubic centimeters of glyoxal solution (01.30% glyoxal content by weight), 6 grams of oxalic acid, and 5 cc. of a 20% aluminum acetate solution. After the fab:

ric wasjpassed through this solution and wasf well wetted out (requiring about '10 seconds im mersion), it was squeezed to remove solution in' theresidual shrinkage in the wash tests is a measure of the efiectiveness of the process. A comparison of the shrinkage of the untreated and of the treated fabric is shown below. The tensile strength and the abrasion resistance of .the fab:' ric were not appreciably affected by the process.

wash test p it lst Wash 2d Wash Untreated Control 5. 6. 0 Treated 1 l. 4

In commercial practice the fabric is washed and slack dried after curing to permit shrinkage resulting in a residual shrinkage of less than one percent in the finished fabric.

f EXAMPLE #2 The fabric described in Example #1 was .immersed for ten seconds in an aqueous impregnating solution containing per'liter, cc. of 30% by weight glyoxal solution, 6 grams of oxalic acid, and 30 cc. of a 20% aluminum acetate solution.

After the fabric was well wetted out it was squeezed to remove solution in excess of pick-up, and was then dried on a pin-tenter frame in air at around 250 F. to the dimensionsbefore impregnating. The dried, tentered fabric was then cured in circulating air at 260 F. for five minutes. The fabric after curing was removed from the pin-frame and subjected to two. CCCT191A cotton wash tests for shrinkage. In the above procedure no shrinkage is permitted during the process so that the residual shrinkage in the wash test is a measure of the effectiveness of the process. A comparison of the shrinkage-of the untreated and'of the treated fabrics is shown below. The tensile strength and the abrasion resistance of the fabric were not appreciably affected by the process.

Warp shrinkage on washing CC'CT-191-A In commercial practice the fabric is washed and slack dried after curing to permit shrinkage resulting in a residual shrinkage of less Pe n lth? finished a i In the above procedure no' InchesP er Yard f than one 1 escorts:

EXAMPIiE flR: V The fabric ofth'e type used in. the previous ex! amples was'iinmer's'ed for tenjsecondslin an aque,

it did' not" requirethe' addition of any oxalic acid) catalyst. After the fabric was well wetted out,

it was squeezed'toremove solution in excess of I30 percent pick-up, and" wasthen dried on a'pim tenter frame in air at around. 250* F. to the. dimensions. beforew impregnating. The dried," tentered fabric was then. cured in circulatingair at 260 FI forfive minutes. The fabric after curing was removed from the pin-frame andsubj'ected to two CCCTI9lf-A. cotton wash tests for shrinkage In the above procedure no shrinkage is permitted during the process so that the residualshrinkage in the wash test is a measure of the effectiveness of the process. A comparison of theshrinkage of: the-untreated and of the treated fabrics is shown below. The tensile strength and the abrasion resistance of. thefabric. was somewhat lowered by this treatment.

' Warpshrinkaye on washing CCC-T1 91-A In commercial practice the fabric is washed and slack dried after cur-ing*,to-permit shrinkage resulting in a residual shrinkage of less than one percent "in the finished fabric.

EXAMPLE #4- The fabric used in Example #1- was immersed for ten-seconds in an aqueous impregnating solution containing'per liter, 12000. of 30% byweight glyoxal solution, 1 gram-oxalic acid, and Ill-grams of potassium-aluminum sulfate. After the-fabric was well wetted out, it was squeezed to remove solution in excess f 130% pick-up and was-then dried on a pin-tenter frame in air at around 250 F. to the dimensions before impregnating. dried, tenteredf'abricwas then cured in circulating-air at 260 F; for five minutes; The fabric aftercuring; was-=removedfrom the pin-frame and subjected to two CCCT191--A- cotton wash tests for shrinkage. In the above proce-- dure noshrinkage ispermitted during the prosess so that the residual shrinkage in the wash tests is a measure of the effectiveness of the process. A-- comparison of the shrinkage of the untreated and of the treated fabric is shownbelow. The tensilestrength and the abrasion. resistance of the fabricwere 'not' appreciably affected by the process.

Inches Per Yard 1st Wash 2d Wash Untreated Control-LL "l;

In commercial practice the'fabri'c--is=- washed- The 5"; and slack driedaften curing; (to. permit? shrinkage;- resulting in. aresi'dualshrinkageofi less than one: percent in; the; finished fabrics Theifa'brio usedxinnthe, previous examples was; immersechforten; seconds in an aqueousimpregnatingsolution;containing per liter cc. of.30%. glyoxal: solution, 6 grams of oxalic acid,,and;.30. grams of.:'a proprietaryimpermanent type of War ter; repellent...(wax-aluminum acetate emulsion) such. as. Aquaroli (supplied by Arkansas Com:-- panic); After the. fabric was passed. throughthis; solutioniand was well wetted out, it was squeezed;

, to remove solutionin excess of pick-up and.

was thenv dried on a pin-tenter frame. in. air at around 250 F. to the dimensions before impregr, hating. The dried, tentered fabric was then cured: in circulating air. at260 F. for five minutes. The; fabric: after: curing. was removed from. the. pinframe-and subjected to twoCCCT-191-A cot.-- tomwashtests-for shrinkage. In the. above: pro;- cedureno shrinkage is permitted during theprocess so that the residual. shrinkage in the wash;

test isa measure of the'effectiveness of. the proc:.-

ess. A comparison of the shrinkageaofitheuuntreated'and ofthe treated fabrics is shown below, The tensile strength and the abrasionresistance: of: the fabric: were, not appreciably. aifectedby the-process. V

Warp shrinkage on washing ccc'-T 19'1 -A;..

wash test I Inches BerYard,

1st Wash 2d Wash.

Untreated Control In commercial practice the fabric is washed and slack dried after curing, to permit shrinkage; resulting in a residual shrinkage of less than onepercent in the finished fabric.

The eifectsproduced 0n the physical properties of'a cellulosic textilefiber by chemical reaction'with glyoxal are probably due to two primary'factors'. Cellulosic fibers, and in particular regeneratedcellulose. fibers, have an' affinity for waterbecause of the presence of the hydroxyl groups 'in the cellulose molecular units. The re.- action of glyoxal' with cellulose as previously postulated results in the removal of hydroxyl groups and the substitution for them of hydrophobic groupsinsensitive to water through the formation of oxyacetylene bridges. The partial solvatioirand consequent swelling with water. of normal cellulose fibers, which causes yarn. and fabric shrinkage, is reduced by the formation of the reactionproduct of cellulose and glyoxal, and shrinkage is thereby" decreased, The improvement in resistance to creasing which isconferred on' cellulose fabrics by reaction with glyoxal'is, We'beIieVe due' to the cross-linking ofmole'cular chainswhich occurs in this reaction with. consequent reduction in the relative slippage of'th'e molecular chains duringatransverse deformation.

It is important that certain practical principles be applied-inthe practice of this proces's. An. acid condition is necessary during the reaction inorder to-obtain' thedesired degree of reaction within a practicable time, but acids'areharmful tocellulose; particularly at elevated temperatures, so that the" minimum amount of acid or acid; producin catalyst requiredto 'producethe 'de' sired result should'be used. Also, for some reason not clearly understood, an excess of glyoxal ''is harmful to the cellulose, so that the minimum quantity of this reagent required'to produce the desired result should also be used. The use of quantities of lyoxal and catalyst in excess of the amounts actually required, is therefore not only economically unsound but is harmful to the fabri The acidity of the commercially available glyoxal solution (it usually has a pH of between 1.00 and 1.30) is not alone sufilcientto cause a reaction with the regenerated cellulose. When such glyoxal is diluted with water in the preparation of the treating bath, the acidity decreases. For

example, if a by weight commercial glyoxal "solution with a ipH'of about 1.12 is diluted with water having a pH of about 7.2 so as to contain about 120 cc. of such glyoxal per liter, the pH is approximately 2.05. When 6 grams of oxalic acid are added to this dilute solution, the acidity is increased to provide a treating bath having a pH of about 1.55. The pH of a solution of 6 grams of oxalic acid per liter of water is about 1.65. The relative'amounts of such glyoxal and acid catalyst in the solution can be varied within limits, which causes some variations in the acidity of the treating bath or liquid. The particular acid catalyst used also causes some variation in the acidity of the treating bath.

Inasrnuch as those acids which are substantially volatile at drying temperatures while in solution, are normally lost with the moisture to a considerable extent during the drying to approximate dryness and early part of the curing period, such volatile acidic components will not normally be available in sufiicient concentration and acidity in the early part of the curing period to cause the reaction between the regenerated cellulose and the glyoxal to occur. Since it is diificult, under plant production conditions, to prevent such loss of a volatile acid, it is preferable to employ an acidic catalyst with an acidic component that increases in acidity and is not eliminated under drying and early curing conditions.

If the catalyst is a salt which dissociates upon the application of heat to produce an acid, the treating solution containing such salt when formed may have a pH of possibly 2.5, yet when that solution is heated to the curing temperature, which happens when the textile material treated with that solution is cured at a temperature above about 212 F., the catalyst salt will dissociate and liberate an acid that changes the :pH of the solution, during the curing to about 1 to 2. When the catalyst is itself an acid, such as oxalic acid, the treating liquid as made up has a pH preferably between about 1.0 and 2.0 for the best results. Summarizing'the treating bath or liquid should be strongly acid and have a pH between about 1.0 and 2.5, preferably between about 1.0 and 2.0 inclusive. The process can be performed on textile material before or after bleaching in the case of materials which are to be bleached. If the process is performed before bleaching. the material is then bleached in a normal manner, using established procedures, without harmful effect on the improved resistance to shrinkage and to creasing and crushing produced by the process. Under certain circumstances a fabric may be treated with this process before dyeing or printing, although in general it will be satisfactory to perform the process after dyeing.

After the treatment of the regenerated cellulosic material with glyoxal in accordance with i our process, the only change in the physical properties of the cellulosic material which we have been able to discover, in addition to its improved crease and crush resistance, is its reduced swelling with water andconsequent reduced shrinkage. We have been unable to note any reduction in the softening point of the cellulosic material under heat treatment as a result of the reaction with the glyoxal.

It has been found that fabric treated in ac- "cordance with this novel method increases in weight by an amount practically equal to the weight of glyoxal applied. Thus a treatment with a solution containing 4.5% glyoxal, cc. per liter of 30% solution), with a liquid pick-up by the fabric of of its weigth, would result in a weight increase in the treated fabric of 5.85% of its original weight. If the glyoxal (solid base) used in the treating solution be from 1.1% to 7.5%, the fabric weight increase limits (with from 80% to possible liquid pick-up) would be from0.88% to 11.25%.

While certain examples have hereinabove been given as illustrative of the utility of the invention, we consider it to be applicable to a wide variety of textile materials including filaments, tow, staple fibers, spun yarns, and fabric of 1. Regenerated cellulose: (11) Viscose; Cuprammonium; (c) Saponified acetate.

2. Mixtures: Major part regenerated cellulose.

In the practice of the invention, the wetting liquid or solution containing the glyoxal and other treating materials may be applied to the textile material in any desired manner, such as by spraying the textile material, While it is traveling, with the treating solution in just the right amount, relative to the rate of travel of the textile material, to give the desired liquid pickup, or even an excess of liquid, or the textile material may be dipped in or otherwise impregnated or saturated withthe treating solution.

All excess treating solution may be removed from the textile material, before the material is cured, in any suitable manner. such as by centrifugalfo-rce, draining, or squeezing. The term wetting, as used in the specification and claims to refer to the application of the treating solution to the textile-materials, is intended to include all means andmethods for applying the treating solution to the textile materials.

The wetted textile -materials are preferably dried, before curing. The wetted fabrics will not have a temperature exceeding about 212 F., even when the drying temperature is above 212 F., but as soonas the wetted fabric dries, it will at once begin to -cure. if the temperature then is above 212 F. Therefore it is safer to dry at a temperature at or below 212 F., and then cure the dried fabric at the desired curing temperature. This makes it possible to more accurately control the curing. a

We claim as our invention:

1. The method of stabilizing, against progressive, dimensional, shrinkage under repeated washings, a textile material predominantly of regenerated cellulose, which comprises wetting the fibers of said materialwith an aqueous liquid having a pH between approximately 1.0 and 2.5 and containing a mixture of glyoxal in approximately 1.12% to. 7.5% by weight in the treating liquid, an aluminum salt which is soluble or readily dispersible in water, and an acid catalyst, the acidic component of which increases in acidity and is not eliminated when concentrated to dryness and subjected to temperatures just above about 212 -F.,- removinghexcess wetting liquid, ithen heating the textile materi'also wetted,:after saidremoval of iexcesssliquidvto-a temperature above about 2123F; for a time interval inversely zrelated to the temperature, until a'rsubstantial tee-action product 'of cellulose and: glyoxal'is formed :i'n situ'in the fibers of saidrma'terial.

' :-2.:The method :of stabilizingagainst progressive dimensional shrinkage under repeatedwas'hings, a textile "material predominantly of re- "generated cellulose," which comprises wetting :the fibers :of said'imaterial withan "aqueous liquid 'rhavin'g a pH between-approximately1.01and 2.0 :and containing a mixture 'of glyoxalrin approxi- -mately'1;12'% to 71.5% byweight in theftreating Iliquid, an aluminum 'salt which 'i'ssoluble or .trea'dily dispersible:in water and' oxalic acid, re moving the iexcess wettingtliquid, Jthen heating the tXtl1eIIlateIi315O wetted; after said removal "of' excess Jiquidyto fa temperature above about 212 F; for 'a' time interval inversely related to the temperature, .;until'ra substantial reaction "product of 50811111058 and' glyoxal is'formed in situ'inthefibers of said material.

"3. .The method'of stabilizing; 'aga'inst progres- .:-sive,dimensiona'l shrinkage underrepeated washings, 1 a itextile "material"predominantly (of regenerated cellulose,'whichec'ompriseswetting the fibers of said material'with' an' aqueousliquid having a pH betweenapproximately"1:0"and 2.5 and containing a mixture oi glyoxalinapproxim'ately 1.12% to 7.5% by weigh't'in the treating liquid, an aluminum salt which is'soluble or readily dispersible in water, and anacidic catalyst the acidic component of which increases in 1 acidity and is not eliminated when concentrated "to dryness and *subjectedztotemperatures just "above about212"F., and said catalyst comprising approximately 0.1%" toif2-%' "by 'weight in the treating liquid, removing excess wetting liquid, then heating the textile material so wetted, after said removal of excess liquid to 'a' temperature above about2l2 "F. for a time interval=inversely related to the temperature, until a substantial reaction product of cellulose and g'lyoxal is formed in situ in 'thefibers of said material.

4. The method of stab lizing, againstprogres- Siva-dimensional shrinkage under repeated washings, a textile material predominantly of regenerated cellulose, which compriseswetting the "fibers of said material with an "aqueous liquid having a pH between approximatelylfl and2.0 and containing a mixture or glyoxal in approximately 1.12% to"7.5% by weight in the'treating liquid, a small amount of an aluminum salt'which is soluble or readily disper's'ible "in water, and oxalic acid in "approximately 0.1'%to'2'% by weight in'thetreating liquid, removing "excess treating liquid, andthen'heating'the textile material so wetted; after-said removal of, excess liquid, to a temperature above about"-'212'F. for a time interval inversely' r'e'lated to'the temperature, until a substantial reaction'product of 'cel lulose and 'glyoxalis formed situ in the fibers of said material.

5. The method of stabilizing, against progressive, dimensional shrinkage under repeated wash- 'ings, a textile materiakpredominantly of "regenerated cellulose, 'whicl'r'comprises' wetting the fibers of said 'material with an aqueous liquid having a pH between approximately 1;0.-and 230 and containing amixture-of glyoxal-inzapproximately 1.12% to "7.5 by-weight in the treating liquid, =from"0.2 to '10 grams per litre of said -.liquid,. of an aluminum saltwhich is soluble'or ,dispersible in water, and oxalic acid in approximately 0.1% to 2% by weight in the treating liquid, removing-excess wetting liquid, drying" the treated fabric "that is free of excess liquid, and then heating the textile'material so wetted, after said removal-of exces liquid, to a temperature above about 212 F. for a time interval inversely related to the temperature, until a substantial reaction product of cellulose and glyoxal is formed in situ in the fibersof said material.

6. The methodof stabilizing,- against progres- 'si-ve, dimensional ishrinkageunder repeated wash- :ings, a textile material predominantly of regenerated cellulose; which comprises wetting the 'fibers of said =material with :an aqueous liquid having a pH between a proximately 1.0 and 2.5 and containing a"miXture-0f g1y0Xal'in approximately 1.12% to 7.5% by weight in the: treating liquid, less than about l0 grams .(solid basis) per litreof said liquid of =-an aluminum salt which is -=so1ub1e-'ordispersible in water, and an acidic-catalyst, the-acidic -component of which increases in acidity andis not eliminated when-concentrated "to dryness and subjected to temperaturesjust above about 212 F., and said -.catalyst-comprising approximately 0.1 to 2 by weight inthe treat- 1 ing :liquid, removing the excess wetting liquid,

then-heating the textile material so wetted, after said removal of'excess liquid, to a temperature inversely related to the temperature, until a substantial reaction productof celluloseand glyoxal is iormedin situ-in the fibers-of said material.

'7. The method of stabilizing, against laundry shrinkage, textile materials -formed predominantly of regenerated cellulose, which comprises "wetting 'said materials with an aqueous solution ,-having-a pH betweenabout :and'2.5 and containing'glyoxal in approximately 1.12% to 725% by "weight in said solution, an raluminumvsalt which is soluble or 'dispers'ible :in water and fibecomesacid'bydissociation in water, and sufficient added 'acidic catalyst to bring the pH of :the solution to about 2.5 :or less, removing the excess wetting solution. and =he ating the -textilematerial so-wetted, .after said removal of "excess solution, to atemperature above 212 F; for a'timeinterval 'inverselyzrelated tothe temperature, until a-substantial' reaction product of cellulose and-glyoxal is'formed'insitu iiithe fibers of said-materials.

"8. The method of stabilizing against laundry shrinkage, textile materials formed predominantly of regenerated cellulose which comprises wetting said materials with an aqueous solution having a pH between about 1.0 and 2.5 and containing glyoxa'l in approximately 1.12% to 7.5% by-weight in said solution, less than about3'% by Volume of aluminum acetate solution containing 20% solids, and sufiicient added acidic catalyst,

the acidic component of which increases in acidity andis not eliminated when concentrated to dryness and subje'cted'to temperatures 'just above about2l2" F.,to bring the pH of the solution below 2.5, removing excess Wetting solution, and heating the textile material so wetted, after said removal of excess solution to 'a temperature above 212 F. for a time interval inversely related to the temperature, until a'substantialreaction product of cellulose and glyoxal is formed :insitu in the'fibers of said materials.

9. The method of stabilizing against laundry shrinkage, "textile materials formed predominantly of regenerated cellulose, which comprises wetting said materials with an aqueous solution having a pH between about 1.0 and 2.0 andcontaining glyoxal in approximately 1.'12%'to"'7=.5'%

13 by weight in said solution, oxalic acid in approximately 0.1% to 2% by weight of said solution, and less than about 3% by volume of aluminum acetate solution containing 20% solids, re-

movin excess wetting solution, and heating the 5 textile material so wetted, after said removal of excess solution, to a temperature above 212 F. for a time interval inversely related to the temperature until a substantial reaction product of cellulose and glyoxal is formed in situ in the fibers of said materials.

EDWARD C. PFEFFER, JR.

JACK EPELBERG.

REFERENCES CITED file of this patent:

Number Number 14 UNITED STATES PATENTS Name Date Heckert May 11, 1937 Pfeffer et al. Feb. 17, 1948 FOREIGN PATENTS Country Date Great Britain 1906 Great Britain Dec. 4, 1935 Great Britain Aug. 4, 1936 Great Britain Oct. 21, 1936 Great Britain Jan. 22, 1937 Great Britain Mar. 1, 1937 Great Britain Feb. 20, 1940 Great Britain Mar. 11, 1940 Great Britain Sept. 15, 1942 

1. THE METHOD OF STABLIZING, AGAINST PROGRESSIVE, DIMENSIONAL SHRINKAGE UNDER REPEATED WASHINGS, A TEXTILE MATERIAL PREDOMINANTLY OF REGENERATED CELLULOSE, WHICH COMPRISES WETTING THE FIBERS OF SAID MATERIAL WITH AN AQUEOUS LIQUID HAVING A PH BETWEEN APPRIXMATELY 1.0 AND 2.5 AND CONTAINING A MIXTURE OF GLYOXAL IN APPROXIMATELY 1.12% TO 7.5% BY WEIGHT IN THE TREATING LIQUID, AN ALUMINUM SALT WHICH IS SOLUBLE OR READILY DISPERSIBLE IN WATER, AND AN ACID CATALYST, THE ACIDIC COMPONENT OF WHICH INCREASES IN ACIDITY AND IS NOT ELIMINATED WHEN CONCENTRATED TO DRYNESS AND SUBJECTED TO TEMPERATURES JUST ABOVE ABOUT 212*F., REMOVING EXCESS WETTING LIQUID, THEN HEATING THE TEXTILE MATERIAL SO WETTED, AFTER SAID REMOVAL OF EXCES LIQUID, TO A TEMPERATURE ABOVE ABOUT 212*F. FOR A TIME INERVAL INVERSELY RELATED TO THE TEMPERATURE, UNTIL A SUBSTANTIAL REACTION PRODUCT OF CELLULOSE AND GLYOXAL IS FORMED IN SITU IN THE FIBERS OF SAID MATERIAL. 